Injection pinch discharge extreme ultraviolet source

1. A source of photons comprising:

a discharge chamber;

first and second groups of ion beam sources in the discharge chamber, each electrostatically accelerating a beam of ions of a buffer gas toward a plasma discharge region, said first group of ion beam sources acting as a cathode and said second group of ion beam sources acting as an anode for delivering a heating current to the plasma discharge region; and

an injector to project a particle of a working substance into the plasma discharge region, wherein the particle is evaporated and ionized by the heating current to form a hot plasma that radiates extreme ultraviolet or soft X-ray photons.

2. A source as defined in claim 1 , wherein said ion beams precede said heating current.

3. A source as defined in claim 1 , wherein said heating current is pulsed and wherein said ion beams comprise pulsed ion beams that precede said pulsed heating current.

4. A source as defined in claim 1 , wherein said ion beam sources comprise continuous ion beam sources and wherein said heating current is pulsed.

5. A source as defined in claim 1 , wherein the particle comprises a liquid droplet of the working substance.

6. A source as defined in claim 1 , wherein the particle comprises a solid pellet of the working substance.

7. A source as defined in claim 1 , wherein the working substance comprises tin.

8. A source as defined in claim 1 , wherein the buffer gas comprises helium, neon or argon.

9. A source as defined in claim 1 , wherein the particle comprises a solid-density particle.

10. A source as defined in claim 1 , wherein the buffer gas comprises a first component of lower atomic number and a second component of higher atomic number, the second component present in a small proportion in order to provide radiation that enhances photoemission from the surface of the injected particle, accelerating its ionization.

11. A source as defined in claim 10 , wherein the first component of the buffer gas comprises helium, neon or argon and the second component of the buffer gas comprises krypton or xenon.

12. A system for generating photons comprising:

a housing defining a discharge chamber;

a gas source for supplying a buffer gas to the discharge chamber;

first and second groups of ion beam sources in the discharge chamber, each electrostatically accelerating a beam of ions of the buffer gas toward a plasma discharge region, said first group of ion beam sources acting as a cathode and said second group of ion beam sources acting as an anode;

a first voltage source for applying an accelerating voltage to said first and second groups of ion beam sources;

a second voltage source for supplying a heating current through the plasma discharge region between said first and second groups of ion beam sources;

an injector to project a particle of a working substance into the plasma discharge region, wherein the particle is evaporated and ionized by the heating current to form a hot plasma that radiates extreme ultraviolet or soft X-ray photons; and

a vacuum system for controlling the pressure of the buffer gas in the discharge chamber.

13. A source of photons comprising:

a discharge chamber containing a buffer gas;

a first group of ion beam sources directed toward a plasma discharge region in the discharge chamber, wherein a component of said first group of ion sources constitutes a first electrode;

a second electrode spaced from the plasma discharge region;

a first power supply for energizing the first group of ion beam sources to electrostatically accelerate gas ion beams of the buffer gas from the first group of ion beam sources toward the plasma discharge region;

an injector to project a particle of a working substance into the plasma discharge region; and

a second power supply coupled between the first and second electrodes for delivering a heating current to the plasma discharge region, wherein the particle is evaporated and ionized by the heating current to form a hot plasma that radiates extreme ultraviolet or soft X-ray photons.

14. A source as defined in claim 13 , wherein said ion beams precede said heating current.

15. A source as defined in claim 13 , wherein said heating current is pulsed and wherein said ion beams comprise pulsed ion beams that precede said pulsed heating current.

16. A source as defined in claim 13 , wherein said ion beam sources comprise continuous ion beam sources and wherein said heating current is pulsed.

17. A source as defined in claim 13 , wherein the particle comprises a liquid droplet of the working substance.

18. A source as defined in claim 13 , wherein the particle comprises a solid pellet of the working substance.

19. A source as defined in claim 13 , wherein the working substance comprises tin.

20. A source as defined in claim 13 , wherein the buffer gas comprises helium, neon or argon.

21. A source as defined in claim 13 , wherein the second electrode comprises a component of a second group of ion beam sources.

22. A source as defined in claim 13 , wherein the particle comprises a solid-density particle.

23. A source as defined in claim 13 , wherein the buffer gas comprises a first component of lower atomic number and a second component of higher atomic number, the second component present in a small proportion in order to provide radiation that enhances photoemission from the surface of the injected particle, accelerating its ionization.

24. A source as defined in claim 23 , wherein the first component comprises helium, neon or argon and the second component comprises krypton or xenon.

25. A system for generating photons, comprising:

a discharge chamber containing a buffer gas;

a first group of ion beam sources directed toward a plasma discharge region in the discharge chamber, wherein a component of said first group of ion sources constitutes a first electrode;

a second electrode spaced from the plasma discharge region;

a first power supply for energizing the first group of ion beam sources to electrostatically accelerate ion beams of the buffer gas from the first group of ion beam sources toward the plasma discharge region;

an injector to project a particle of a working substance into the plasma discharge region;

a second power supply coupled between the first and second electrodes for delivering a heating current to the plasma discharge region, wherein the particle is evaporated and ionized by the heating current to form a hot plasma that radiates extreme ultraviolet or soft X-ray photons; and

a vacuum system for controlling the pressure of the buffer gas in the discharge chamber.

26. A system for generating photons as defined in claim 25 , wherein the second electrode comprises a component of a second group of ion beam sources.

27. A method for generating photons, comprising:

electrostatically accelerating a plurality of beams of ions of a buffer gas toward a plasma discharge region;

injecting a particle of a working material into the discharge region; and

supplying a heating current through the plasma discharge region, wherein the particle is evaporated and ionized by the heating current to form a hot plasma that radiates extreme ultraviolet or soft X-ray photons.